I. Biodiversity A. The variety of life in an area B. Increases the stability of an ecosystem (e.g multiple food sources for predators)

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2 I. Biodiversity A. The variety of life in an area B. Increases the stability of an ecosystem (e.g multiple food sources for predators)

3 C. 3 types: 1. Genetic diversity: variety of genes in a population 2. Species diversity: number of different species 3. Ecosystem diversity: different types of ecosystems leads to species diversity

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5 II. Threats to biodiversity A. Extinction: disappearance of a species from all or part of its range 1. Background: gradual process, due to long-term changes 2. Mass extinction: when a large percentage of species go extinct (dinosaurs)

6 B. Overexploitation 1. Excessive use of resources for profit 2. Tragedy of the commons individuals not motivated to conserve public resources for the welfare of others, instead they take what they can for themselves while it is still available

7 C. Habitat Loss 1. Destruction due to agriculture and suburban sprawl 2. Disruption of food webs Keystone species: a species that plays a large role in an ecosystem, its disappearance can cause a dramatic shift in an ecosystem

8 Some starfish may perform this function by preying on sea urchins, mussels, and other shellfish that have no other natural predators. If the sea star is removed from the ecosystem, the mussel population explodes uncontrollably, driving out most other species, while the urchin population annihilates coral reefs.

9 D. Habitat Fragmentation 1. Separation of an ecosystem into small pieces or islands 2. Smaller island --> smaller populations --> more vulnerable

10 E. Pollution 1. Anything that makes the environment less fit to live in 2.Some examples: hazardous waste, solid waste (5 pounds per person per day!), noise pollution, thermal pollution, chemical pollutants 3.Can be in the soil, water, or air

11 4. Example: DDT a)perfect pesticide: cheap, active for long time, kills many insects b)perfect hazardous pollutant: Non-biodegradable (can t be broken down by natural processes), Cannot be eliminated from body

12 c)biological magnification 1)Toxic substance (DDT) becomes more concentrated at higher trophic levels in a food chain 2)Top carnivores at highest risk 3)Bald eagle populations threatened with extinction because of DDT

13 Fish-Eating Birds Large Fish 10,000,000 1,000,000 Small Fish Zooplankton Producers 100,000 10,000 1,000 Water 1

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15 5.Example: Eutrophication a)accelerated aging of lakes due to pollutants like N and P b)step 1 - nitrogen+phosphorus in the water = excessive growth c)step 2 - overpopulated algae = decreased light, algae die off d)step 3 - Bacteria eat the dead algae and use up O2 in lake. e)step 4 - fish die from lack of Oxygen

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18 6.Example: Greenhouse effect a)caused by pollutants such as CO 2 & methane b)they allow solar heat in, and trap it in c)global temperatures rise d)leads to changes in weather, melting ice caps, rising sea levels

19 Satellite imagery shows where carbon dioxide is being emitted or absorbed, measured here in Reds show sources; blues, absorption. (Credit: NASA)

20 7.Example: Acid Rain a)so2(burning Coal) + NO(Cars) b)no + H2O = HNO3 (Nitric Acid Rain) c)so2 + H2O= H2SO4 (Sulfuric Acid Rain)

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24 Effects of Acid Rain a)can Sicken or Kill plants b) Lowers PH in Lakes/Rivers C) Can Cause lakes to release stored Heavy metals(mercury) * Can kill Fish

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27 Acid Rain in Minnesota Northern Lakes Have Granite No Buffer action More Problems Southern Lakes Have LIMESTONE * Buffers Acid! Less Problems

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29 F. Invasive Species 1.Organisms transported by humans into new habitats 2.No limits to population growth in new habitat(no predators or parasites) 3.Cause extinction of native species, human health problems, damage to structures

30 Purple Loosestrife

31 Gypsy Moth

32 Eurasian Water milfoil

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34 IV.Conservation of Resources A. Use of resources in U.S lbs of garbage/person/day gallons of water/person/day 3. more than 200 million metric tons of pollutants are released into the atmosphere each year 4. Refrigerators account for 20% of household energy use

35 B.Two types of natural resources 1.Renewable - can be replenished through natural processes Wood, cotton, air, water, sun, soil 2.Nonrenewable - once it is used, it cannot be replaced Coal, oil, metals, minerals

36 C.Sustainable Use 1.Using resources at a rate that does not deplete them 2.Improved farming methods reduces soil erosion and water consumption Cover crops, terracing, crop rotation 3.Fishing regulations limits catches to prevent overfishing

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38 D.Natural pest control 1.Avoid overuse of chemicals 2.Bring in natural enemies a)lady bugs eat aphids b)some larva (e.g. Gypsy Moth) can be attacked with parasites 3.Pheromones (scent meant to attract mates) to lure insects into traps 4.Release sterile males

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40 E.New practices focus on conserving ecosystems 1.Focus on biodiversity hotspots, to preserve endemic species (only found in that location) 2.Focus on ecosystems that provide services like wetlands 3.Conserve habitat and all the species that live there

41 F. Conserving on a local scale 1.Reduce 2.Reuse 3.Recycle

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